Aim: To investigate the association of gene expression of MMP-2 and -9, and TIMP-1, -2, -3, and -4 and polymorphism frequencies of MMP-9 C1562T and plasma MMP-9 enzyme activity in lung cancer patients. Methods: In this study, DNA and RNA samples were extracted from peripheral blood of 300 subjects (200 lung cancer patients and 100 controls). MMP-9 C1562T polymorphism was determined using restriction fragment length polymorphism (RFLP) method, and expression of MMP-2 and -9, TIMP-1,-2,-3, and -4 was determined using reverse transcriptase polymerase chain reaction. Plasma MMP-9 enzyme activity levels were measured using enzyme-linked immunosorbent assay. Results and Conclusion: The frequencies of C1562T genotypes were found to be CC 67%, CT 30%, and TT 3% in the control group and CC 75%, CT 24%, and TT 1% in the patient group. It was determined that CC genotype frequency increases significantly in patients according to control group. Plasma MMP-9 enzyme activity levels increased in patients with lung cancer compared to the control group. The cut-off value of MMP-9 enzyme activity was determined as 7.76 ng/mL by receiver operating characteristics curve analysis. The sensitivity, specificity, positive predictive value, and negative predictive value were 77%, 51%, 75.9%, and 52.6%, respectively. The expression of MMP-2 and TIMP-1 was found to be higher in lung cancer patients. Finally, we claim that determination of MMP-9 enzyme levels and expression of MMP-2 and -9 and TIMP-1 can be used as a marker in lung cancer.